In many heavy industries it is desirable to employ large box-like load containers for receiving and temporarily storing raw materials or intermediate products for later processing or for subsequent delivery to other locations. Such load containers may have a capacity of several dozen metric tons or even more and are often provided with integral legs or associated stands and frames for supporting the containers on the ground or plant floor both when the containers are empty and out of use and when they are filled and temporarily storing material. Often a heavy duty carrier is provided for lifting and transporting such load containers from place to place.
One prior art device of this general nature is the Scrap Bucket Carrier disclosed in U.S. Pat. No. 4,618,307, which issued to the same assignee as the present application. In that patent, a heavy duty carrier is shown for lifting and transporting a scrap bucket or the like supported in a legged stand. The carrier includes a trailer with a gooseneck-like member connected to a two-wheeled tractor. A hydraulic cylinder on the tractor operates through a parallelogram linkage to raise and lower the trailer gooseneck and thus the forward portion of the trailer. One or more additional hydraulic cylinders interconnect the rear of the trailer frame and the members on which the trailer wheels are mounted for raising and lowering the rear portion of the trailer.
Also in the aforementioned patent, the stand is formed with a generally rectangular frame with rigid legs depending from the four corners thereof. A scrap bucket with a clam-shell opening bottom is supported in the stand and the carrier trailer may be lowered and backed up between the legs and under the frame. When the carrier trailer is elevated the stand and the bucket are picked up for transport to another location. The bucket is provided with a large bail handle which, with the aid of a separate crane or the like, permits the bucket to be lifted out of the stand and repositioned for discharging the contents by opening the clam-shell bottom.
Another general type of heavy duty carrier in the prior art is the kind of ladle or slag pot carrier disclosed in U.S. Pat. No. 4,624,618 (or the patents to Kress cited therein) where a large ladle or pot is picked up by a cradle pivotally mounted on the carrier trailer and the cradle is swingable in an upward and rearward direction in order to tilt the ladle and thereby dump its contents. Such carriers have been specifically designed to pick up, transport, dump and set down ladles and pots and, in general, are not suitable for use in handling other types of bulk containers such as, for example, dump boxes.